diff --git a/.github/workflows/downstream-version-bumps.yml b/.github/workflows/downstream-version-bumps.yml
index 68ae9482..065e10a1 100644
--- a/.github/workflows/downstream-version-bumps.yml
+++ b/.github/workflows/downstream-version-bumps.yml
@@ -233,7 +233,8 @@ jobs:
 
             clone_dir="$(mktemp -d)"
             gh repo clone "$TARGET_REPOSITORY" "$clone_dir" -- --depth 1
-            branch="ci/${issue_number}-$(date -u +%Y%m%d)-bump-${component}-${version}"
+            version_slug="${version//./-}"
+            branch="ci/${issue_number}-$(date -u +%Y%m%d)-bump-${component}-${version_slug}"
             git -C "$clone_dir" switch --create "$branch"
 
             bump_args=(
diff --git a/tests/test_github_workflows.py b/tests/test_github_workflows.py
index 368ddabe..99c65cba 100644
--- a/tests/test_github_workflows.py
+++ b/tests/test_github_workflows.py
@@ -198,6 +198,8 @@ def test_downstream_version_bumps_are_release_triggered_idempotent_and_review_ga
     assert "gh pr create" in run_commands
     assert "uv lock --upgrade-package base-cli" in run_commands
     assert 'git -C "$clone_dir" push --set-upstream origin' in run_commands
+    assert 'version_slug="${version//./-}"' in run_commands
+    assert 'bump-${component}-${version_slug}' in run_commands
     assert "gh pr merge" not in run_commands